Hysterical Blindness

• WWizards of the Coast2011-09-22
  Official Ruling
  Hysterical Blindness's effect will continue to apply to a creature even if you (or a teammate) gains control of that creature later in the turn.
• WWizards of the Coast2011-09-22
  Official Ruling
  Only creatures controlled by your opponent when Hysterical Blindness resolves will get -4/-0. Creatures that enter or that an opponent gains control of later in the turn will be unaffected.

Rulings via Scryfall